No we want parallel vision. Check the technique with some stereograms 3D images... if the image pops off the page you are using parallel view if they cave in then you are crossing your eyes.
If you're concerned that you are crossing your eyes. Skip the blip page for a while and just use soft focus and notice the whites of the page, the margins of the book and the corners. use the imaginary X technique. When you're ready the blip page will return naturally using parallel vision.
Alex